Justin Burnell’s side had hoped to pick up a much-needed win at London Scottish but were out-played by opponents who were 36-3 up after just 57 minutes.
Although Rotherham scored tries from flanker Tom Calladine and scrum-half Matthew Walsh late on, Brett Connon adding a conversion to his first-half penalty, it did not disguise how worrying things are becoming at Clifton Lane.
Scottish had been vanquished 37-5 by troubled London Welsh on Christmas Eve but easily swept aside their South Yorkshire visitors, who are now sitting just 11 points above the relegation place.
Atkinson scored inside eight minute and there was further tries for scrum-half Ed Hoadley, winger Jason Harries and centre Patrick Kelly before the interval, full-back Peter Lydon adding three conversions and a penalty for a 29-3 lead.
He improved Robert Fergusson’s 57th-minute try, too, as Rotherham struggled for any foothold in the game.
They had a quartet of Northampton Saints player on dual-registration – Howard Packman, Rory Hutchinson, Lewis Ludlam and Jordan Onojaife – as well as Ollie Bryant from Leicester Tigers, while Callum Wilson came in from Ealing, too.
However, the fresh faces did little to prevent 10th-placed Titans from falling to another loss and they remain with just four league wins this term.
London Scottish: Lydon; Holland, Fergusson, Kelly, Harries; Cullen, Hoadley; Shiel, Turner, Koroi, Bartle, Hunter-Hill, Kenny, Atkinson, Sisi. Replacements: Walker, Harris, Cringle, McGeekie, Douglas, Coombes, Galbraith.
Rotherham Titans: Thomas; Wilson, Hutchinson, Bryant, Packman; Connon, Walsh; Tom Williams, Maddison, Herriott, Salmon, Hicks, Onojaife, Calladine, Ludlam. Replacements: Graham, Toby Williams, Williams, Normandale, Curry, Ryan, Barker.